Reduced expression of β2 integrin genes in rat peripheral leukocytes by inhibiting postprandial hyperglycemia

S100 Genes are Highly Expressed in Peripheral Leukocytes of Type 2 Diabetes Mellitus Patients Treated with Dietary Therapy

Background and Objectives

We demonstrated that the mRNA induction of S100s in rat peripheral leukocytes by severe hyperglycemia was reduced by inhibiting postprandial hyperglycemia. Here, we compared inflammatory gene expression in peripheral leukocytes between type 2 diabetes mellitus (T2DM) patients undergoing dietary therapy alone and healthy volunteers, and between T2DM patients undergoing dietary therapy alone and those undergoing such therapy in combination with drug therapy using the α-glucosidase inhibitor miglitol.

Methods

T2DM patients who had undertaken dietary therapy alone or in combination with drug therapy using miglitol for ≥ 8 weeks and healthy volunteers were subjected to a meal tolerance test and glucose concentration, neutrophil elastase concentration, and mRNA expression analyses of peripheral leukocytes by microarray and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) immediately before and 180 min after a meal.

Results

Blood glucose concentrations 60 min after a meal were lower in T2DM patients with dietary + miglitol therapy than in those with dietary therapy alone. Neutrophil elastase concentrations at 60 and 120 min after a meal were lower in T2DM patients with dietary + miglitol therapy than in those with dietary therapy alone. Expression levels of S100A8 in a fasting state and S100A6, S100A8, and S100A9 180 min after a meal were higher in T2DM patients with dietary therapy alone than in healthy volunteers. Expression levels of S100A12 in a fasting state and 180 min after a meal were higher in T2DM patients with dietary therapy alone than in T2DM patients with dietary + miglitol therapy.

Conclusions

S100 genes were more highly expressed in T2DM patients with dietary therapy than in healthy volunteers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-020-00334-z.

Changes in peripheral inflammation-related gene expression by postprandial glycemic response in healthy Japanese men

OBJECTIVES

Continuous postprandial hyperglycemia is associated with the onset of cardiovascular disease. In recent years, the mRNA expression of inflammation-related genes in peripheral blood leukocytes has been shown to be induced by an increase in blood glucose levels. The aim of this study was to investigate differences in the expression of inflammation-related genes in peripheral blood leukocytes in response to an increase in blood glucose from individuals who consumed two kinds of breakfast meals with different glycemic indexes (GIs).

METHODS

Twenty healthy Japanese men 40 to 70 y of age were given low- or high-GI meals for breakfast for 14 d. Clinical examinations were performed on days 7 and 14. Their blood glucose levels and insulin concentrations were measured from before breakfast ingestion to 120 min after. Additionally, using the blood obtained before and 120 min after breakfast, the mRNA expression levels of inflammation-related genes in peripheral leukocytes were measured.

RESULTS

The blood glucose levels were significantly lower in the low-GI meal intake group at 30, 60, and 120 min after breakfast than in the high-GI meal intake group. The intake of high-GI meals for 6 d led to an increase in the mRNA levels of interleukin-1β, S100A4, and CD18 compared with the period of low-GI meals.

CONCLUSION

The intake of a low-GI breakfast for 1 wk in healthy Japanese men resulted in lower postprandial blood glucose and insulin levels, which were accompanied by a reduced expression of inflammation-related genes in peripheral blood leukocytes.

Glucose and TNF enhance expression of TNF and IL1B, and histone H3 acetylation and K4/K36 methylation, in juvenile macrophage cells

Hyperglycemia activates innate leukocytes such as monocytes and induces pro-inflammatory cytokine expression, resulting in increased monocyte adhesion to aortic endothelial cells. In this study, we investigated whether high glucose and/or tumor necrosis factor (TNF) would enhance pro-inflammatory cytokine expression of tumor necrosis factor (TNF) and interleukin (IL)-1β (IL1B) by altering histone modifications in U937, a juvenile macrophage cell line. The mRNA levels of TNF and IL1B in U937 cells were significantly affected by glucose concentration and TNF treatment. Mono-methylated histone H3K4 signals around TNF and IL1B were lower in cells treated with high glucose compared with low glucose. Conversely, tri-methylated histone H3K4 and H3K36 signals were higher in cells treated with high glucose compared with low glucose. TNF treatment of U937 cells cultured in high glucose enhanced histone H3K36 tri-methylation, particularly around the gene regions of TNF and IL1B. Histone acetylation was induced by treatment with TNF in high-glucose medium. The induction of acetylation and tri-methylation of K4 and K36 of histone H3 around TNF and IL1B by treatment with high glucose and/or TNF was positively associated with the induction of these genes in juvenile macrophage U937 cells.

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Culture with high glucose induced TNF and IL1B expression in U937 cells.

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TNF treatment enhanced high glucose inducible TNF expression in U937 cells.

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H3K4me3 around TNF and IL1B was induced by high glucose treatment.

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TNF treatment enhanced H3Ac in the gene body region of TNF and IL1B.

The Effects of Folic Acid Administration on Cardiac Oxidative Stress and Cardiovascular Biomarkers in Diabetic Rats

The aim of this study was to examine the effects of folic acid administration on the antioxidant enzyme (superoxide dismutase (SOD) and catalase (CAT)) activities, lactate and malate dehydrogenase (LDH and MDH) activities, and certain LDH and MDH isoform distribution in the cardiac tissue of diabetic Wistar male rats. Diabetes mellitus (DM) was induced by streptozotocin (STZ). There were five groups: C1-control (physiological saline 1 ml/kg, i.p. one day), C2-control with daily physiological saline treatment (1 ml/kg, i.p. 28 days), DM-diabetes mellitus (STZ 100 mg/kg in physiological saline, i.p. one day), FA-folic acid (5 mg/kg in physiological saline, i.p. 28 days), and DM+FA-diabetes mellitus and folic acid group (STZ 100 mg/kg in physiological saline, i.p. one day, and folic acid 5 mg/kg in physiological saline, i.p. 28 days). After four weeks, animal hearts were isolated for measurement of enzyme activities, as well as for histomorphometry analyses. An elevated glucose level and a decreased insulin level were obtained in the DM group. SOD, CAT, and MDH activities were elevated in the DM group, while there was no difference in LDH activity among the groups. In all tested groups, four LDH and three MDH isoforms were detected in the heart tissue, but with differences in their relative activities among the groups. Left ventricular cardiomyocyte transversal diameters were significantly smaller in both diabetic groups. Folic acid treatment of diabetic rats induced a reduced glucose level and reduced CAT, SOD, and MDH activities and alleviated the decrease in cardiomyocyte diameters. In conclusion, increased activities of antioxidant enzymes and MDH may be the consequence of oxidative stress caused by DM. Administration of the folic acid has a protective effect since it leads to reduction in glycemia and activities of the certain examined enzymes in the rats with experimentally induced DM.

Fasting during the suckling-weaning transient period of rats induces inflammatory gene expression in the adipose tissue and peripheral leukocytes

OBJECTIVE

Nutritional deficiency during developmental stages could be associated with subsequent development of inflammation-related metabolic abnormalities. In this study, we examined the effects of a 3-d fast during the suckling-weaning transient period of rats, and subsequent intake of high-fat-high-sucrose (HF) and low-fat-high-starch (LF) diets in adulthood, on the expression of inflammatory genes in adipose tissue and peripheral leukocytes.

METHODS

Male Sprague-Dawley rats were deprived of food for 3 d during the suckling-weaning transient period, and were subsequently fed an HF or LF diet for 14 wk from 17 wk of age. Serum monocyte chemoattractant protein-1 (MCP-1) concentration and mRNA levels of inflammatory genes in mesenteric adipose tissues were assessed at 31 wk of age. The mRNA levels of inflammatory genes at 0 h and 2 h after oral glucose load at 30 wk of age in peripheral leukocytes were measured.

RESULTS

Fasting induced circulating MCP-1 protein in rats fed an LF diet but not an HF diet. The HF diet induced high mRNA levels of tumor necrosis factor-α, interleukin-1β, and S100 proteins in peripheral leukocytes at 2 h after glucose load in fasted rats when compared with controls. Expression of CD11c, an activated macrophage marker, was induced in the fasted group given an HF diet during adulthood.

CONCLUSIONS

Fasting rats during the suckling-weaning transient period and an HF diet intake during adulthood enhance inflammation by promoting the expression of inflammatory genes in adipose tissue and peripheral leukocytes.

Effects of intravenous glucose and lipids on innate immune cell activation in healthy, obese, and type 2 diabetic subjects

Atherosclerosis/cardiovascular disease are major causes of morbidity/mortality in obesity and type 2 diabetes (T2D), and have been associated with activation of innate immune cells, their diapedesis to the arterial intima and formation of the atherosclerotic plaque. While in obesity/T2D immune cell activation likely depends on dysregulated metabolism, the interaction between individual metabolic factors typical of these conditions (hyperglycemia, hyperlipidemia), innate immune cell activation, and the progression of atherosclerosis remains unclear. We, therefore, measured by flow cytometry cell surface expression of CD11b, CD14, CD16, CD62L, and CD66b, known markers of granulocyte (Gc) and monocyte (Mc) activation, in five healthy, five obese, and five T2D subjects, during 4-h i.v. infusions of 20% dextrose (raising blood sugar levels to ~220 mg/dL), 20% Intralipid (raising trygliceride levels to ~6 mmol/L), or a combination of the two. We hypothesized that both glucose and lipids would increase Gc/Mc surface marker expression, and simultaneous infusion would have an additive or synergistic effect. Surprisingly, though, infusion of glucose alone had little effect, while lipids, alone or combined with glucose, significantly increased expression of several markers (such as CD11b in Gc and Mc, and CD66 b in GC) within 60-90 min. Less pronounced increases in systemic inflammatory cytokines also occurred in obese and T2D subject, with no acute changes in gene expression of the the proinflammatory genes NFκB and CCR2. Our results suggest that lipids may be stronger acute contributors to innate cell activation than acute hyperglycemia per se, possibly helping shape more effective preventive dietary guidelines in T2D.

Experimental and clinical evidences for glucose control in intensive care: is infused glucose the key point for study interpretation?

Stress-induced hyperglycemia has been considered an adaptive mechanism to stress up to the first intensive insulin therapy trial, which showed a 34% reduction in relative risk of in-hospital mortality when normalizing blood glucose levels. Further trials had conflicting results and, at present, stress-induced hyperglycemia management remains non-consensual. These findings could be explained by discrepancies in trials, notably regarding the approach to treat hyperglycemia: high versus restrictive caloric intake. Stress-induced hyperglycemia is a frequent complication during intensive care unit stay and is associated with a higher mortality. It results from an imbalance between insulin and counter-regulatory hormones, increased neoglucogenesis, and the cytokine-induced insulin-resistant state of tissues. In this review, we summarize detrimental effects of hyperglycemia on organs in the critically ill (peripheric and central nervous, liver, immune system, kidney, and cardiovascular system). Finally, we show clinical and experimental evidence of potential benefits from glucose and insulin administration, notably on metabolism, immunity, and the cardiovascular system.

Dietary supplementation with (-)-epigallocatechin-3-gallate reduces inflammatory response in adipose tissue of non-obese type 2 diabetic Goto-Kakizaki (GK) rats

(-)-Epigallocatechin gallate (EGCG), a major catechin in green tea, is an antioxidant associated with the reduction of oxidative stress in vitro. However, the mechanisms underlying the effects of EGCG on adipose tissue-related metabolic disturbances in vivo are not understood. This study examined whether dietary supplementation of EGCG reduces the oxidative stress-associated inflammatory response in the mesenteric adipose tissue of non-obese type 2 diabetic Goto-Kakizaki (GK) rats. GK rats were fed a normal diet or diet containing 0.1, 0.2, or 0.5% EGCG (w/w) for 25 weeks. The mRNA levels of IL-1β were significantly reduced in GK rats given 0.1% EGCG (0.059 ± 0.008; means ± SEM in arbitrary unit) compared with those in GK rats given a control diet (0.135 ± 0.011), but not in those given 0.2% EGCG (0.123 ± 0.012) or 0.5% EGCG (0.112 ± 0.019). The mRNA and protein level of other genes for inflammatory responses such as IL-18, TNF-α, MCP-1, CD11s, CD18, and resistin were also significantly reduced in rats given 0.1% EGCG, but not in those given ≥ 0.2% EGCG. This suggests that supplementation with EGCG at relatively low concentrations (0.1%) in GK rats reduces expression of genes and proteins involved in inflammation in adipose tissue.